(1) Field of the Invention
The invention relates to the technical field consisting of equipment for various pipe networks, including, in particular, hydrocarbon refineries, gas-processing plants, and even petrochemical factories. The invention relates specifically to a movable shutter for a fluid conduit, a fluid-treatment facility, and a procedure for the secure closure of a movable shutter for a fluid conduit.
(2) Description of Related Art
Many currently known sliding shutters allow fluid conduits to be equipped in such a way that they can shift from an open position to a closed position or vice-versa. For example, document FR 2733024 proposes the sliding shutter shown in FIGS. 1, 2, 3, 4a, and 4b. It is composed of:
two half-bodies 2, 3 associated with a locking mechanism that allows them to be brought close together or separated from each other. Each of the half-bodies 2, 3 includes a tube 21, 31 that forms a conduit and allows the passage of the fluid. Each of the ends of the tube 21, 31 is secured respectively to a flange 22, 32 and to a plate 23, 33. Each plate 23, 33 has a rear surface that is connected to the tube 21, 31, as well as a bearing surface 231, 331; and
a flat gate 1, shown in greater detail in FIG. 5, which is movably mounted between the bearing surfaces 231, 331 of the plates 23, 33. The gate 1 is composed of a body 11 divided into two parts that are symmetrical in relation to the transverse median plane 14. The body 11 has two flat longitudinal surfaces 111, 112 that are parallel to each other. The first portion 12 is a solid portion that, in a closed position (see FIG. 4a) blocks the conduit in such a way as to prevent the flow of fluid between the two half-bodies 2, 3. Fittings 121 are provided on each of the longitudinal surfaces 111, 112, which fittings are suitable for being aligned with the tubes 21, 31 when the shutter 1 is in the closed position. The second portion 13 is a portion that is pierced by an opening 131 whose edges are flush with each of the longitudinal surfaces 111, 112. In the open position (see FIG. 4b), the pierced portion 13 is positioned at the center of the conduit, aligned with the tubes 21, 31, so as to allow the circulation of fluid between the two half-bodies 2, 3.
The locking mechanism is composed of four clevis fasteners 6a, 6b, 6c, 6d that are parallel to the axis of the half-bodies 2, 3 and that are joined to the half-bodies by means of:
two drive shafts 4a, 4b, affixed to a first half-body 2; and
two driven shafts 5a, 5b affixed to the second half-body 3.
The rotation of the drive shafts 4a, 4b causes the half-bodies 2, 3 to move closer together or farther apart. The simultaneous rotation of the two drive shafts 4a, 4b is ensured thanks to two cranks that form an integral part of one of the ends of each of the shafts 4a, 4b. The cranks are connected to each other by a tie rod 7. A lever 8 that forms an integral part of one of the cranks allows the rotational movement to be performed.
The locking mechanism is suitable for allowing the half-bodies 2, 3 to shift from a position in which they are separated from each other to a position in which they are close to each other. In FIGS. 1 and 3, the locking mechanism holds the plates 23, 33 in a separated position in which the bearing surface 231, 331 of the plates is spaced apart from the respective longitudinal surface 111, 112 of the gate 1. This configuration allows the gate 1 to be shifted between the closed and open positions.
After the locking mechanism has been actuated, the half-bodies 2, 3 are in the position shown schematically in FIGS. 2, 4a, and 4b, in which they are close together. In this close position, the bearing surfaces 231, 331 clamp together the body 11 in a leakproof manner so as to hold the gate 1 in the open or closed position. Each of the bearing surfaces 231, 331 comes into close contact with the respective longitudinal surface 111, 112 of the gate 1. FIG. 4a is a schematic representation of the case in which the gate 1 is in the closed position, while FIG. 4b shows the case in which the gate 1 is in the open position.
Document FR 2733024 also describes seals 9 that are located on both of the longitudinal surfaces 111, 112 of the gate 1. These seals 9 are located around the opening 131 and around the fitting 121.
The movable shutter described above has the disadvantage of providing no way to confirm the proper position of the gate between the two plates. Indeed, poor positioning can have serious consequences for the facility, causing fluid leaks and endangering the operators.
Document WO 9214957 describes a movable shutter that makes it possible to avoid some of the above-mentioned disadvantages. It proposes a system that allows the position of the gate to be secured. The system is composed of a locking pin that can sink into two holes provided in the lateral surfaces of the body of the gate, with the position of these holes corresponding respectively to the open position and the closed position of the shutter. This safety system prevents the gate from being shifted whenever the half-bodies are not completely released in the second position. However, such a system is difficult to implement, because the holes in the gate must be formed in very specific positions. Furthermore, the installation and use of the locking pin are complex, because the operator must place the pin in the proper hole.
Other documents were also consulted, namely, documents U.S. Pat. Nos. 3,738,610, 2,462,494, and 3,613,720.
Document U.S. Pat. No. 3,738,610 describes a valve that is actuated by a pivoted bi-faced tap. A flange extends axially from a ring that defines a groove on both sides of the ring. A ring of flexible sealing material is secured in the ring. Part of the ring facing the flexible seal rings includes annular beads, each having a peak and whose sides slope toward the planar surface of the corresponding ring. Planar sealing surfaces of the flange may be clamped against similar planar sealing surfaces on the seating ring secured to each valve body, so as to ensure leakproofness.
Document U.S. Pat. No. 2,462,494 describes a pipeline fitting with sealing means provided with peripheral annular shoulders on internal planar surfaces. The peripheral annular shoulders cooperate with sections of the body in order to ensure leakproofness. The pipeline fitting includes a part that forms an orifice plate and a blinding plate, which can tilt and pivot.
Document U.S. Pat. No. 3,613,720 describes a swinging check valve in which a part forming a valve shutter has a flap with a seal equipped with tabs that ensure the proper alignment of a valve-body seat and a clamping connective assembly.